Combustion system for hot-blast stoves



Oct. 21 1924. A. N. DIEHL COMBUSTION SYSTEM FOR HOT BLAST STOVES Filed May 26,

1922 4 Sheets-Sheet 1 [ma en for.

Wines-89s M W M m CV x w v w W 1% Oct. .21 1924. 1,512,583

A. N. DIEHL COMBUSTION SYSTEM FOR HOT BLAST STOVES Filed'May 26, 1922 AIShEG'tS-ShEG t 2 Oct 21 1924. 1,512,583

A. N. DIEHL COMBUSTION SYSTEM'FOR HOT BLAST STOVES Filed y 6. 4 Sheets-Sheet a 1,512,583 A. N. DIEHL COMBUSTION SYSTEM FOR HOT BLAST STOVES Oct. 21-. 1924.

Filed May 26, 9 2 4 Sheets-Sheet 4 j'nveniorx 4y" JZW A Patented a. 21, 1924.

'mnnosn it. mean, or DUQUESNE, rmmsxnvan'n.

COMBUSTION SYSTEM FOR HOT-BLAST STOVES.

Application filed Kay 26,-1922. Serial No. 563,829.

To all whom it may canoe-m: Be it known that I, -AMBROSE N. DIEHL, a citizen of the United States, and resident of Duquesne, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Combustion Systems for Hot-Blast Stoves, of which the following is a specification.

This invention relates to hot blast stoves and has for one of its objects the provision of ahea'ting system for hot blast stoves whereby the flow of gases to thestove will be automatically regulated so as to provide a substantially constant flow.

Another object of the invention is the provision of a system of this class in which the air-supply is re ulated and controlled sons to provide a su stantiall'y constant flow of airin sufficient volume to support. combustion of the gases being supplied.-

' A further object of the invention is to providea novel form of mixer whereby the gas and air will 'be thoroughly mixed before entering the stoves- 2 A still further object of theinventiou is to provide a system of this class that will automatically regulate a battery of stoves simultaneously;

Referring to the drawings illustral ing the invention Figure 1 is a sectional elevation through a hot blast stove, having the invention applied thereto.

Figure 2 is a sectional plan on the line llII of Figure 1.

Figure 3 is a. side elevation of a battery of four stoves, having the invention applied thereto.

' Figure 4 is an enlarged detail of the mixer nozzle partly in section. I

Figure 5 is an enlarged detail of the forward section of the mixing chamber .partly in section.

Figure 6 it a rear elevation of the forward section of the mixing chamber.

Figure 7 is a sectional .plan through the gas supply conduit on the line VIP-VII of Figure 1, showing the butterfly control valve.

The invention is shown applied to a twopass stove of standard design com rising an outer cylindrical wall 2, a dome-s aped top 3, a central combustion chamber 4, and a surrounding checkerwork 5. The checkerwork 5 opens at its lower end into suitable 'fiues 6 which communicate leading to the stack 8. Y

The stove is adapted to be fired with blast furnace gases and is, therefore, provided, with a suitable mixer which comprises a with a stack flue 7 hollow substantially cylindrical body portron 9 forming a mixing chamber 'havinga. gas inlet 10, a nozzle member 11 arranged centrally within the mixing chamber 9, and provided with a ta ring forward end 12. The nozzle is'provi cd with a series of circumferential rows of holes or'apertures 13 forming outlets for the air and which extend forwardly on an angle of approximately 30 degrees to the axis of thenozzle and the mixing chamber. An annular air chamber 14 is arranged around the mixing chamber adjacentits forward end and is provided with inlet holes or apertures 15 which extend tangentially through the wallof. the chamber 9 on forwardly. extending angles of approximately 30 degrees to the axis of the chamber 9, so that the air entering throughthese apertures is given a forward centrifugal motion which is im arted to the column of gases flowing throug the chamber and insures a thorough mixing of the air and gas. It will also be seen that p the an ular arrangement of the holes 13 and 15 in t e nozzle 11 and in the mixing chamher 9, respectively, cause the. air to flow across the line of. flow of the gases and thus to more thoroughly mix therewith. 'The mixture of combustible gases andair is delivered through the tube or conduit 4 into the lower end of the combustion chamber 4 and there ignites and is burned.

Gases are supplied to the mixer through the inlet 10 by a conduit 16 leading main 1? and provided with a suitable butterfiy valve 18 intermediate its ends adaptfrom 0.

ed to regulate the flow of gas therethrough. l

A suitable blower 19 having a direct dllV- ing connection with a motor 20 is provided cnstant sup for supplying asubstantially ply of air to the mixer through its nozz 11 and air chamber 14. Suitable conduits 21 and 22 lead from the blowerto the nozzle 11 and air chamber 14, respectively. The

blower '19 is of a wellpknownioentrifugal type, the housing perimeter .;bein in the form of a spiral, an

the wheel or an being" i of the backward curved type, haviog main.

floats or blades and intermediate floats or blades all curved backward'or away from the direction of rotation. The blower 19, due

' -culated operatingconditions and the pressure at any other air delivery point lessthan the calculated volume, is as near constant as possible. Therefore, if the pres sure in the mixer rises to a certain predetermined amount, no air will be delivered .by the blower 19, and consequently no air will be forced into the gas conduit at the mixer .to create an explosion hazard.

The butterfly valve 18 is adapted to' be automatically controlled by an incremental A float type regulator comprising a container 24 having a quantity of oil or other fluid 25 therein and having a bell 26 floating in said fluid; The bell 26-has a hollow inner drum 27 of somewhat smaller diameter attached concentrically thereto. The drum 27 supplies the buo ant force necessary to overcome the weight of. the bell. A pipe or branch conduit 28 leads from the' conduit 16 at a point below the valve 18 to the regu- .a point above the. uid level and within the bell '26 -to supplies lator and extends u gas pressure under the bell.

The bell 26 is connected by a chain 29 to the circumference of a sheave wheel 30 mounted. on a frame support 31 above the bell and provided with a radially extending arm 32. A chain 33 has one end connected bya radially adjustable connection 34 to the arm 32 and is connected intermediate its end to the circumference of a sheave wheel 35 on the butterfly valveshaft 36. The free end of the chain 33 is provided with a counter-Weight 37 adapted to keep the chain taut so that any movement of the bell 26 will be communicated through chain 29, wheel 30, arm 32 and chain 33 to the sheave 35 and valve 18.

The purpose of the arm 32 is to provide adjustment in the motion of the regulator or bell transmitted to the butterfly valve 18 to compensate for the flow characteristics of the butterfly valve.

In Figure 3 a battery of four stoves is' shown controlled by a single regulator. In this construction the air and [gas is supplied to the mixer the same as when only one stove'is controlled. however, in order to get the best results from the regulator it has been found advisable to have an average of the gas pressures in all the four gas sup ply conduits 16 operate the bell 26 of the' regulator, and therefore the conduits 16 are connected in pairs by pipes 39 and these pipes are connected midway between their ends to a pipe 40, which in turn is connected midway between its ends to a pipe or conduit .thesheave 35 in the same manner as the chain 33 in the sin is construction. However, the valve '18 in t e other three stoves are each operated .bychains 33? connected to the next precedin valve sheave'35 and to their sheave 35, an each chain is provided with a counterweight 37 to keep it taut. By

thefirst stove being this construction it will be seen that the operation of the sheave 35 on the first stove sheaves on each succeeding stove.

The operation of this system is as follows: Assuming that the regulator and mixer are designed to operate at a pressure equal to, or-slightly lower, than the minimimnpressure ever attained in the gas supply main as for example at one and one-half'inches of water.,'

- will cause a simultaneous movement of the Due to the drum 27 which furnishes a buoyant force equal to the weight of the bell' 26, and the counterweights 42 on top of'the drum which exert a downward force equivalent to the normal operatingpressure desired for the stove, the bell w1ll assume a certain definite position. Assuming the bell at this initial position, any increase in pressure in the conduit 16 will be communicated to the underside of the bell 26 'through the pipe 28 or 41, and the bell will rise, thus releasing the valve operating chains and gradually close the valves 18. The bell 26 will continue to rise until the valves 18 have throttled the conduits 16 sufficiently to reduce the pressure to a point where it will not be suflicient .to raise the bellfarther. At this point the bell will remain until some further increase or decrease in gas pressure tends to-again cause it to rise or fall. It is evident that due to the change in the buoyant effect of the drum 27 as the .bell rises or falls, the movement of the bell from the initial position, and consequently the variation in pressure in the conduit 16, will be much less violent and irre ular than were the bell not equipped with the drum. The drum in addition to supplying the buoyant force necessaryto balance the bell thus serves to give the regulator bell a definite position for any. given pressure within it, and acts as a stabllizer on the movement of the bell 26 and the butterfly valve 18 to which the bellis connected, thus dampening the efl'ect "of the fluctuations in pressure in the supply mainand in consequence giving a practically uniform pressure at the mixer.

It will thus be seen that by maintaining a substantially constant supply of gas and air, and by thoroughly mixing the two, as

described above, a correctly proportioned and "minedp combustion volumes lburned', resulting in a much er stove efiicien'cy than heretofore obrclaimzee system for hot blast {stoves comprising a gas and air mixer, a

conduit leading from said mixer into the. co njaustion chamber of said stove, means "for supplying a substantially, constant sup- .g ly of airunder ,pressure, to "said mixer, a

gas supply-gonduitfor supplying gas -to' said mixer, a valve insa'id conduit, and

firieiins operable by the gas pressure in said ,-.'in to .said mixerr. 4 2i A'.combustion" system for hot blast conduit for operating said valve so as to cause :a substantially constant 'fi'ovv of gas stoves'comprising a. gas and air mixer, a

"kconduit leading fromsaid mixer into the {combustion chamber of said stove, means Lfor supplying a substantially constant supply of'air under pressure .to saidmixer, a

valve "insaid conduit, and a float oper- -.-.a;ted incremental typeregulator for operat in saidvalve so as to cause a substantia 1y constant owo-f gas into said mixer, said "regulator eing operable by the. gas pressure said conduit below said. valve.

'. Sf'A combustion system 'for hot blast stoves comprisingagas and. air mixer, a conduit leading from said mixer into the,

combustion chamber of said stove, means i for supplying a substantially constant. supply of air under pressure to said mixer, a

g s. supply conduit for supplying gas to- ,said mixer, a valve in said conduit, andy a float operated incremental. type regulator for operating said valve, a branch conduit leading from below.- the valve in said gas supply conduit to. the float of said regulator "so as to cause-a substantially constant flow of gas into said-mixer.

. 4. .A. combustion system for hot blast stoves comprising a gas and air mixer, a conduit leading from said mixer into the {combustion chamber of said stove, a' motor driven blower forsupplying a substantially constant supply of 8.11 under pressure to said mixer," a gas supply. conduit for supplyingrgas to said mixer, a butterfly. valve in said- -conduit,a float operated incremental type regulator for operating-"said valve, a branch conduit leading frombfelow the valve in said gassupply conduitto the float'of said regulatoradapted .to supply gas to operate said regui: r sojas' to cause a substantially constant fiow of gas into said mixer. F

5. A combustion system'for a battery of hot blast stoves comprising a gas and air mixer for each of said stoves, conduits leading from said mixers-into the combustion chambers of said stoves, means for 'supplying a substantially constant supply, of air under pressure to said mixers, gas supply .ing from said mixers into the combustion chambers of said stoves, independent motor .driven blowers for supplying a substantially constant supply of air under pressure to said mixers, independent gas supply conduits for supplying gas to each of said mixers, a butterfly valve in each of said conduits for regulating the flow of gas to said mixers, a float operated incremental ty'pe re ulator adapted to operate all 'of said valves simultaneously and branch conduits leading from below the valves in said as supply conduits to the float of said regu ator and adapted to supply gusto operate said regulator so as to cause a substantially constant flow of gas into said mixers} In' testimony whereof, I have hereunto set in hand. AMBROSE N. DIEHL. 

